Transmitting arrangements, particularly in devices of mobile radio communication, usually have a power transistor which is followed by an antenna. The characteristics of a real antenna which change in operation can cause a mismatch of the power transistor to an impedance value of the antenna. The cause of such changes is mainly the changes in the environmental conditions of the antenna caused by the user of a device of the mobile radio communication. The device can be located, for example, in a hand, on a metallic base or in a vehicle.